The disclosed embodiments of the present invention relate to controlling a stereo camera, and more particularly, to a method and an apparatus for stereoscopic focus control of a stereo camera.
With the development of science and technology, users are pursing stereoscopic and more real images rather than high-quality images. There are two techniques of present stereoscopic image display. One is to use a video output apparatus, which collaborates with glasses (such as anaglyph glasses, polarization glasses or shutter glasses), while the other one is to use only a video output apparatus without any accompanying glasses. No matter which technique is utilized, the main theory of stereoscopic image display is to make the left eye and the right eye see different images, and thus the brain will regard different images seen from two eyes as a stereoscopic image.
One way to create the stereoscopic image contents is to use a stereo camera. When the stereo camera is used for capturing a scene, an autofocus function may be enabled to automatically determine the optimal focal settings for two sensors of the stereo camera. The conventional autofocus function may be implemented using a master-slave mechanism or a free-run mechanism. In a case where the master-slave mechanism is employed, one sensor acts as a master sensor, while the other sensor acts as a slave sensor. Therefore, the focal setting determined for the maser sensor would be directly used as the focal setting of the slave sensor. In other words, both of the sensors of the stereo camera would have the same focal setting. As a result, the image captured by the master sensor has clear objects that are in focus; ideally, the image captured by the slave sensor is supposed to have clear objects that are also in focus. However, as both of the sensors of the stereo camera use the same focal setting, the manufacture and/or calibration error between the master sensor and the slave sensor would result in uneven image quality, i.e. one in-focus and the other out-of-focus, which leads to poor stereoscopic visual perception.
In another case where the free-run mechanism is employed, the focal settings of the sensors of the stereo camera are determined independently. In other words, the focal setting of one sensor is allowed to be different from the focal setting of the other sensor. However, the image captured by the one sensor may have clear objects that are in focus at a first depth, while the image captured by the other sensor may have clear objects that are in focus at a second depth different from the first depth. For example, the images respectively captured by the sensors may have different focused objects in respective central focus regions.